Articolo in rivista, 2009, ENG, 10.1016/j.jmmm.2008.09.011

Study of Sb substitution for Pr in the Pr0.67Ba0.33MnO3 system

Garg, K.B.; Nordblad, P.; Heinonen, M.; Panwar, N.; Sen, V.; Bondino, F.; Magnano, E.; Carleschi, E.; Parmigiani, F.; Agarwal, S.K

Department of Physics, University of Rajasthan, Jaipur, 302004 Rajasthan, India Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala, Sweden Department of Material Science, Turku University, Turku, 20014, Finland Superconductivity and Cryogenics Division, National Physical Laboratory, Dr. K S Krishnan Marg, New Delhi, 110012, India CNR-Laboratorio Nazionale TASC-INFM, Area Science Park, I-34012 Basovizza, TS, Italy

WestudytheeffectofSbsubstitutionforPrinthehole-dopedsystemPr0.67Ba0.33MnO3 (PBMO)for different dopinglevelsofSb.Thetwoelectricalresistivitytransitionsobservedinthepristinesample PBMOshifttolowtemperaturesonSbdopingwithanoverallincreaseintheelectricalresistivity.The significantlocallatticedistortionandthegrainboundaryeffectscausedbythelargecationsize mismatchbetweenPr3+ and Sb3+ suppressesthedouble-exchange(DE)interactionandenhancesthe super-exchange(SE)interaction.Thecompoundsshowasignificantandincreasingvalueof magnetoresistanceattemperaturesbelowtheCurietemperature,notexpectedfromtheDEmodel. The CurietemperaturedecreaseswithincreaseinSbcontentbutthesaturationmagnetizationislittle affectedbythesubstitution.Thespins,however,staywellalignedinthelow-temperatureregime.Our X-raynear-edgeabsorptionspectra(XANES)andcorelevelphotoemission(XPS)dataclearlyshowthe Sb cationtobein+3stateandruleoutanypossibilityofe-dopinginourcompounds.

Journal of magnetism and magnetic materials 321

Keywords

Manganite, SQUID, X-ray photoemission, XANES, Magnetoresistance

CNR authors

Carleschi Emanuela, Parmigiani Fulvio, Bondino Federica, Magnano Elena

CNR institutes

INFM – Centro di responsabilità scientifica INFM, IOM – Istituto officina dei materiali